Fuel feeding mechanism for mechanical stokers



Nov. 17, 1931. M. ALPERN 1,832,682

FUEL FEEDING MECHANISM FOR MECHANICAL STOKERS Filed p 1926 3 Sheets-Sheet l Nov. 17, 1931. M. ALPERN 1,832,682

FUEL FEEDING MECHANISM FOR MECHANICAL STOKERS Filed Sept. 29, 1926 5 Sheets-Sheet 2 N ox r. 1 7, 1931. M. ALPERN 1,832,682

FUEL FEEDING MECHANISM FOR MECHANICAL STOKERS Filed Sept 29, 1926 3 Sheets-Sheet 3 Patented Nov. 17, 1931 un ts!) STATES PATENT OFFICE MAXXVELL ALPERN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T'O AMERICAN ENGINEERING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA FUEL FEEDING MECHANISM FOR IVIECHANIOAL STOKIERS Application filed September 29, 1926. Serial No. 138,469.

' thereof shall substantially comprise a plurality of independently adjustable pusners, so that fuel may be fed to any part of the furnace at a greater average rate than any other part thereof.

Another object of my invention is to provide stolzer apparatus comprising a plurality of pushers constituting one wall of a retort, means whereby .thexposition of the path of travel of at least one of the pushcrs may be adj ustcd independently of that of the others,

and means whereby the throw of one or more of the pushers may be independently adjusted. I

A further object of my invention is to providea Stoker wherein adjacent pushers in any part of the retort may have different strokes, so that a desired slicing effect may be had on the fuel.

Uther objects and applications of my invention, as well as details of construction and operation, whereby my invention may be practiced, willappear more fully hereinafter, when taken in connection with the accom panying drawings, wherein 1 is a longitudinal sectional view of an I inclined underfeed stoker embodying my inyention, the sectional plane being taken on the line ll of Fig. 2, the primary and secondary pnshers being illustrated. in their maximum advanced positions;

Fig. 2 is a partial bottom plan view of the structure of Fig. 1;

Fig. 3 is an enlarged detail view, partially V in longitudinal section and partially in elevation of the lost-motion connection between the pusher and the operating mechanism, the

Fig. 5 is an enlarged detail end elevational view of the mechanism for independently adjustinp; the stroke of the pusher groups, the sectional plane being taken on the line 5-5 of Fig. l; and

Fig. 6 is an enlarged, longitudinal sectional view of the stroke-adjusting mechanism of F ig. 5 and connected parts taken on the line 66 of F ig. 2.

In the illustrated embodiment of my invention shown in the drawings, a furnace 1 comprises a stoker 2 of the inclined underfe-ed type and it is provided with any desired number of series of tuyeres 3 which extend downwardly from a fuel; opening 4 in a furnace front wall to a rear end 6 of said furnace. Between each pair of series of tuyercs 3 is positioned: av stoker retort 7, an upper end 8 of which terminates in the fuel opening 4. This opening may be supplied with fuel from a hopper 9 which delivers into a casing 11 communicating directly 'with the retort entrance 4. Fuel from the hopper 9 may be forcibly fedthrough the retort opening 4 by means of a primary pusher 12 which is slidably mounted in the casing 11. A lower rear end 13 of the retort 7 is'operatively associated with an extension grate 14 slidably mounted on a framework 15 which also serves to support the seriesof tuyeres 3.

A desired portion 16 of a retort bottom 'wall 17 may comprise a series of secondary pushers 18 which are slidably mounted in stepped relation on guides 19 supported by spaced side plates 21, as illustrated in my Patent No 1.443.202, granted to the American Engineering Company January 23, 1923. The present pushers 18, however, embody the further feature of a scraping bar 22 which serves to prevent the escape of siftine's between adjacent pushers as well as the jamming of the pushers 18 on their slides 19 due to accumulations of siftings. As shown in Fig. 1, the scraper bar 22 may be loosely positioned in a transversely extending groove 23 on the underside of the pusher 18 and it is provided with a bevel edge 24 to facilitate the scraping action.

Heret'ofore, when feeding fuel into furnaces, either on grates or through underfeed retorts, it has been the practice to have a graduated feed from the front to the rear of the stoker or from the rear to the front. In such constructions, should the fuel bed become too thin at any point, as a result of the character of the coal or through an error on the part of the operator, it is not possible to feed more fuel directly to that point and thereby fill the hole. Furthermore, such constructions do not permit relative movements of the fuel which serve to assist both the rate and efiiciency of fuel burning. Thus, it has been found that for certain fuels, by reason of the high clinkerage tendency of the ash and the high percentage of ash in the fuel, the rate of feed at the rear end of the stoker should be greatly in excess of that at any other point. Experience has shown that with fuels of this character, not infrequently it is very desirable to have adjacent pushers operate at different average rates in order to obtain a slicing effect on the fuel by such relative movement.

As a result of my present invention, the above problems have been satisfactorily solved, so that a greater or less amount of fuel may be fed to any desired part of the furnace and a greater or less amount of ash fed therefrom. The apparatus for accom plishing these desired results comprises, in addition to the aforesaid parts, a plurality of individual driving or power-transmitting means 2 26 and 27 for independent second ary pusher units 28, 29 and 31, respectively, the several driving means having lost-motion connections 32, 33 and 34 with a common actuating mechanism 35 which has a lostmotion connection 36 with the primary fuel pusher 12, all as will appear in greater detail hereinafter.

The intermediate and front pusher units 28 and 29 may each comprise three'pushers and the same may be true of the rear unit 31, but only one pusher has been here shown. Each of the pushers 18 is provided with an integral rack 37 (Fi gs. 3 and 4) which is caston a front underside portion 38 thereof, and it is engaged by a segmental gear mounted on a pin 41 supported by bearings 42 extending from the side plates 21. A lever 4?; is provided with spaced end portions 44 which are mounted on the pin 4-1 on oppositesides of the segmental gear 39. The lever 43 is also provided with an intermediate portion 45 forming a shoulder 46 adapted to abut againsta corresponding shoulder 47 on the segmental gear 39 when the secondary pusher 18 is to be projected rearwardly into the retort 7 and the fuel advanced from the bottom of said retort.

The segmental gear 3.) is further provided with an adjustable abutment 48 in the form of a bolt 49 which is threaded in a lug 50 of the segmental gear 39 and terminates in an adjusting handle 51. The adjustable abutment 48 is positioned to engage the intermediate portion 4-5 of the lever 43 when the secondary pusher 18 is to be returned from its projected position shown in Fig. 1. to its front or retracted position. The bolt 49 thus provides an adjustable lost-motion connection 52 between the operating lever 413 and the secondary pusher 18, whereby the stroke or fuel f eding rate thereof may be varied from zero to a maximum value determined by the movement of the ope 'ating lever -13. Mince each of the secondary pushers 18 is provided with such operating mechanism. the stroke or throw of the pushers in each group may be independently adjusted and such adiustment will not affect the stroke of the individual pushers in the other groups. Therefore, the stroke of any pusher 18 may be increased to a value greater than that of each of the other secondary pushers.

An opposite end 53 of the operating lever is also bifurcated to receive thcrebetween an operating member or link 54 and it is connected thereto by means of a pivot pin "he operating member 5% is used in connection with the intermediate pusher group 28 and the outer pusher group 29, whereby the levers $3 of these groups may be simultaneously operated. The single pusher in the rear or inner unit 31 is also provided with a somewhat similar operating member 50 having a pivotal connection 57 to an inner end 58 of a link 59, an opposite end ('31 of which is pivotally connected to an adjacent end (22 of a rod 63 which is slidably mounted at said end in a bracket 64- supportcd by the side plates 21. The end 58 of the link 59 is also connected to the movable extension grate i l by means of a centrally pivoted lever (35. a link 66, and an extension grate rod 67. The movement of the link 59 thus causes the operation of the extension grate l land the rear pusher unit 31. The stroke of the latter may be adjusted independently of the extension grate lei by reason of the lost-motion connection 52.

As shown in l ig. 2, the link 59 'n'cferably comprises a central member 68, opposite ends of which are respectively positioned in threaded borings formed in end members 71 and 72, whereby the overall length thereof may be varied should it be desirable to adjust the position of the extension grate LI and the rear pusher unit 31 with respect to the remaining pusher units.

The operating member a l of the intermediate pushcr group 28 is provided with a bracket 73 which may be moved longitudinally thereof from one desired position to another. The bracket 73 provides a pivotal mounting for one end 7%; of a link 75. an opposite end 76 of which is pivotally connected to an inner end 77 of a rod 78 slidably Lesa-cs2 mounted in a bearing afiorded'by thebracket 64. "Such longitudinal adjustment of the bracket 78 permits the position o'fth'e path The front pusher group 29 adjacent to'the fuel entrance 4-. is somewhat similarly connected bya link 79 to a sleeve 81 which is adjust-ably mounted on a rod 82 slidably mounted in a third bearing afforded bythe bracket The adjustment'of the sleeve 81 on the rod 82 accomplishesthesame purpose as the adjustment of the bracket 73 on the operating incmberfial oi the intermediate pusher group 28.

The longitudinally slidable rods 63, 7 8 and are preferably supported by the bracket 64 in a common plane. These rods are similarly supported in bearings 83 (Figs. 1 and 6) provided by a lower section 84 of a twoparthousing 85, an upper section 86 of which is removably clamped to said lower part by bolts 87 (Fig. Each of the slidable rods has an extended portion 88 of reduced diameter providing a shoulder '89 atone end and and (S3 and when the rack 95 is moved in the opposite direction, it engages-the outer adjustable abutment-s 92, 98 and 9% of the respective rods just mentioned. The lower rack 95, which thus serves as a common operating member for the independent driving means 25, '26 and 27, constitutes one part of the reciprocable actuating mechanism 35.

Under conditions of operation, when the several secondary pushers 18 are withdrawn from the retort 7 to thedcsircd extent, as determined by the adjustable members 81, 73,

and 68, the lover rack 95 is in its extreme rear position and in engagement with the shoulders 89 of the several rods 78, 82 and 68. lVheu the lower 'ack 95 in its extreme outer position, as-shown in 1, it is in engagement with the outeradjus'table abutnients 92, 9-53 and 94; and the secondary pushers 18 occupy their extreme rear or projected positions.

\Vhen it desired'to vary the stroke or, throw of any one of the rods 78, and 63 indcj'iendently of: each of the others, the outer adjustable abutment of said rod ismoved to a new position. i F or example, should itbe desirable to cause the intermediate pusher so turned asto decrease the lost-motion connection 32 between its rod 78 'and the-rack 95. Such adjustmentin no way ali'ects'the inclividualadjustment of the pushers insaid-intermechate group 28 or the r'emannnggroups and a further independent 'iLClIlUStDTQllt may be madeat the pushers by means oi their lostmotion connections 52, so that, for example, only one of the pushers of saidi'n'termediate group is actuated. Similar adjustments may be made for the remaining groups. The stroke of the extension grate 14 maybe'controlled independently of the rear pusher unit 31 byproperly adjusting the rod abutment 94; and the lost-motion connection 52 at the pusher.

The lower rack 95 may be actuated by means of a pinion 97 which is mounted ona shaft 98 supported by the two-part housing 85, the pinion being actuated by an upper rack 99 slidably mounted in the walls of the upper housing section 86. The racks 95 and 99 and the pinion 97 constitute the essential elements of the reciprocatory actuating mechanism tured to receive a threaded end 101 of a pusher-rod 102 having spaced abutments 103 and 101 positioned in the, path of travel of a shoulder portion 105 of the primary pusher 12, thereby forming the lost-motion connection 86. The outer abutment 10 1 may be adjustably mounted on the pusher rod 102, whereby the stroke of the lower rack and consequently that of all the secondary pushers 18 may be simultaneously varied at will.

Assuming the secondary 'pushers 1'8to be in the projected position shown in Fig. 1 and the several rod abutments 92, 93 and 9st so adjusted that the strokes of their corresponding rods are equal, a forward movement oi the primary pusher 12 from engagement with the inner abutment 103 into engagement with the outer abutment 10 causes no operation of the secondary pushers 18 by reason of the lostmotion connection 36 at this point. A further movement of the primary pusher 12, however, causes the abutment 104 to be actuated for the remainder of the stroke of said primary pusher. The resulting movement of the pusherrod 102 causes an opposite movement of the lower rapk '95 from engagement with the several rod abutments 92, 93 and 9% into engagement with the inner shoulders 89 thereof. The continued movement of the lower rack 95 for the remainder of its stroke causes a forward movement of the pusher units 28, 29 and 30, the point at which the individual pushers 18 of these groups are actuated being determined by the lost-motion connections hen the primary pusher 12 is moved in the opposite direction to feed fuel from the hopper 9 through. the opening 4: into the re tort 7, the several pushers 18 are projected into the retort 7 at intervals detern'iined by the setting of the shaft abutments 92, 93 and The upper rack 99 is aper- 94-. and the adjustable abutments 48, so that fuel may be fed to any part of the furnace lire at a greater rate than any of the other parts or the ashes may be fed therefrom at a greater or less rate.

While I have shown only one embodiment of my invention, for the purpose of describ ing the same and illustrating its principles of construction and operation, it is apparent that various changes and modifications may be made therein without departing from the spirit of my invention, and I desire, therefore, that only such limitations shall be imposed thereon as are indicated in the appended claims or as are demanded by the prior art.

I claim:

1. A stoker retort having a series of groups of pushers constituting the bottom of said retort, means whereby the strokes of said groups of pushers may be relatively adjusted and the strokes of the pushers in each group may be adjusted, individual motion-transmitting means for said groups, and common actuating means for said individual motiontransmitting means.

2. A stoker having a retort provided. with at least two groups of pushers, individual driving means for said groups of pushers, the pushers in each group having lcs -motion connections to their individual driving means, a primary pusher, and means for so connecting said individual driving means and said primary pusher that the stroke of said individual driving means may be independently controlled and the stroke of earl) of said pusher groups as a whole varied thereby.

3. A retort provided with a plurality of grc ups of pushers constituting a movable bot tom wall thereof, individual power-transmitting means for said groups. the connection between each power-transmitting means and its respective group being such that the stroke of one of the pushers in said last-mentioned group may be varied independently of that of the others, primary actuating means, and means connecting said last-mentioned means and said individual power-transmitting means whereby the stroke of the latter may be independently controlled and the stroke of each of the groups of piahers as a whole 'aried thereby.

for

for actuating said rack and a lever having a lost-motion connection to said gear, acommon operating member for the levers of each group, actuating means, a rack driven thereby, and linkage for so connecting said driven rack and said groups that the average fuel feeding rate of the latter may be independently adjusted.

6. In combination, a plurality of groups of pushers. each pusher having a rack, a gear positioned to engage said rack and a lever having lost-motion connection to said gear, a common ope 'ating member for the levers of each group, actuating means, a rack driven thereby, a plurality oi rods having lDClGPOllCl-I ently adjustable lost-motion connections to said driven rack, and linkage for respectively connecting said rods and said operating members.

7. A furnace having a stokcr provided'i with a plurality of groups of pushers, each pusher having a rack, a gear in mesh with said rack and a lever having a lost-motion connection to said gear, a common operating meml or for the levers of each group, actuat-r ing means, a rack driven thereby, a plurality of rods having independently adjustable lost-motion connections to said driven rack, and means including linkage whereby said rods and said respective operating mQIHlJQlSTTLS may be adjustably connected.

8. A stoker having a fuel retort, a plurality of pushers movable in the bottom of said rctort, mechanism for actuating said pushers, motion-transmitting means connecting thez 'iee pushers with said mechanism, said transmitting means including adjustable means For regulating the stroke of a plurality of said pushers as a unit, and independent means for individually adjusting the stroke of at least one of said pushers within said unitary group.

9. A stoker having a fuel retort, a plurality of pushers movable in the bottom of said retort, mechanism for actuating said pushers; motion-transmitting means for connecting the pushers and said mechanism,v said transmitting means including adjustment means affecting the stroke of a plurality of said pushers as a group, and independent adjust- 1 ment means affecting the stroke of an individual pusher of said group.

10. A. stoker having a fuel retort, a plurality of pushers movable in the bottom of said retort, mechanism for actuating said pushers; "L motion-transmitting means connecting the pushers and said mechanism, said transmitting means including adjustment means for regulating the length of stroke of a plurality of said pushers as a group, other means for regulating the lengths of the strokes of the individual pushers within said group, ant. adjustment means also included in said transmitting means for determining the paths in which the said strokes occur.

11. A stoker having a fuel retort, a plurality of pushers movable in the bottom of said retort, said pushers being actuatable in groups, a common actuating mechanism, and means for connecting the mechanism with said groups, said connecting means including adjustment means for regulating the strokes of said groups, adjustment means also included in said connecting means for individually regulating the strokes oi? the pushers of the respective groups, and other adjustment means for determining the relative positions of said groups.

12. A furnace having a stoker provided with a plurality of groups of pushers, mechanism for actuating said pushers, means connecting the pushers with said mechanism, said connecting means including adjustment means for independently regulating the length of stroke of the individual groups, and other adjustment means confined to the inclividual groups for regulating the strokes of the individual pushers.

13. A furnace having a stoker provided with a plurality of groups of pushers, a common operating member for the pushers 01 each group, adjustable connectionsbetween the operating members and the pushers of the respective groups afifording independent regulation of the strokes of the individual pushers, actuating means, and means for independently connecting said operating members with said actuating means, said lastnamed connecting means being adjustable to independently regulate the length of the strokes of the individual groups.

14. A furnace having a stoker provided with a plurality of groups of pushers, a common operating member for the pushers of each group, adjustable connections between the operating members and the pushers of the respective groups aifording independent regulation of the strokes of the individual pushers, actuating means, means 'for independently connecting said operating members with said actuating means, said lastnamed connecting means being adjustable to independently regulate the length of the strokes of the individual groups, and adjustment means also associated with the said last-named connecting means for independently regulating the paths in which the said groups are movable.

MAXWELL ALPERN. 

